Insulator



March 12, 1935. A. o. AUSTIN INSULATOR Filed May 1'7, 1930 IN VENTOR m M f N w M A 4 A 0 0 m r A Patented Mar. 12, 1935 UNITED STATES INSULATOR Arthur 0. Austin, near Barberton, Ohio, assignor, by mesne assignments, to The Ohio Brass Company, Mansfield, Ohio, a corporation of New Jersey Application May 17, 1930, Serial No. 453,180

32 Claims.

This invention relates to insulators subjected to mechanical stresses and has for its object the provision of devices of this class which shall be of improved construction and operation and which are adapted to accommodate themselves to conditions of stress and temperature to which they are subjected.

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawings and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawings:

Fig. l is an elevation with parts in section showing one embodiment of the present invention.

Figs. 2, 3, 4 and 5 are fragmentary sectional views showing modified forms of bearings for the invention.

In suspension insulators or insulators used in tension of the usual cap and pin form, there is a tendency for the metallic parts to distort under heavy load. In addition, the differential expansion between the metal and porcelain also tends to change the relation of stress both in the metal and the dielectric. Under some conditions the distortion of the metal may permit the rearrangement of stress in the dielectric such that the dielectric member will be cracked, destroying its electrical reliability. One of the chief difficulties, particularly on insulators of high mechanical strength, is the radial distortion of the cap.

Fig. 1 shows one method of correcting this defeet. The dielectric member 10 is cemented into a cap 13. A pin 69 is cemented in a recess in the head of the dielectric member. When load is applied to the cap 13 and pin 69 by their attaching means, there is a tendency to pull the dielectric head out of the cap 13. The resultant pressure tends to expand the cap 13. This will permit the dielectric member to deform and crack under the stress. In order to offset the expansion of the cap 13, the head of the dielectric member is given wedge shaped bearing surfaces 62. The tapered bearing surfaces 62 will maintain pressure against the cement by slipping down as the cap expands from increased temperature or due to the load. These surfaces are preferably smooth and provided with roller bearings 66. The remainder of the head is preferably relieved from any stress by dipping or otherwise applying a yielding coating 16.. It is evident that while the expansion of the cap may be compensated for, it is also evi dent that the cap can set up a very heavy pressure tending to pinch the head off under low tempera" ture conditions, particularly where the load or tension on the insulator is slight. In order to relieve this maximum stress which tends to shear off the head, two methods may be used. The radial stress set up by the cap may be reduced by providing it with slots 17 suitably spaced as shown in my prior Patent No. 1,284,976, dated Nov. 19, 1918. This tends to taper off the radial pressure and minimize the danger of shearing, particular- 1y under low temperatures. This construction has distinct advantages over a construction where the cement is allowed to slip in the cap. In the latter case the tangential forces in the cement tend to make it difficult to control the pressure between the dielectric and the cement. Where the dielectric, however, has a tapered head, the cement being comparatively weak in tension can always expand and permit adjustment of the head for a distortion in the cap.

In insulators having large bearing surfaces, the reduction of the diameter of the head, due to its tapered form, is very material where the stress is carried on a single bearing surface extending for a considerable distance along the axis of the insulator. This may be offset as shown in Fig. 1. In this case several tapered surfaces 62 are provided on the outside of the head of the dielectric 10. These surfaces are preferably provided with roller bearings as previously explained and the head coated with a yielding material 16. The angularity of the tapered bearing surfaces 62 may be changed so that the stress may be tapered off at the end surfaces and the heaviest load placed on the middle surface. This tends to reduce the shearing stress and permits of an increased load being placed on the insulator without danger of causing a stress which will crack the dielectric. The stress on the inner surface may be carried by a cement joint, the load being distributed by the use of bearing surfaces 60 and resilient rollers 63, as will be more fully explained. As heavy loads or tensions on the insulator usually occur at low temperatures, there is a tendency for the cap to contract under these conditions and compensate for deformation caused by the stresses set up by the load. In this case, it may not be necessary to apply any compensation to the cap, particularly where the latter has a heavy cross section. The pin, however, has a tendency to contract and relieve the stress as well as the ocment, which usually has a lower linear coefficient of expansion for temperature changes. By providing the outer surface of the pin with slipping surfaces 60, as shown in 1, it is possible to maintain the radial force on the cement 65 between the surface of the dielectric 10 and the pin 69. As previously explained, this surface is preferably provided with rollers 63. Where slipping is desired, it is necessary to use some material on the surface, for if Portland cement is used in direct contact with the metal, there is likely to be a slight bond between the cement and surface in time so that slipping will not take place except at excessive loads.

In the form of the invention shown in Fig. 1, the pin is provided with bearing faces 60. The

ered by metal layers 68. In operation, a load is applied at the end of the pin 69 and to the cap portion 70. The load tends to draw the pin outward and the cap portion over the head of the insulator. By providing the outer surface of the insulator with small antifriction bearing members 66, it is possible to use a fairly flat angle for the bearing faces which will allow relative move-- ment of the parts under load in the direction of 'the applied force of the load, and compensate for the diametrical distortion of the cap. The members 66 may be in the form of small rollers or balls, or in the form of rings extending around the dielectric and circular in cross section. These rings may be continuous or in pieces, as desired,

or wound in the form of a spiral. The bearing members 65 have a rolling action which will permit of adjustment of the connected parts with a much flatter angle of the bearing faces than could be used if the effective cceificient of friction were higher. It is, therefore, possible to use an angle which together with the comparative free movement of the rolling members 20 will permit the parts to return to their normal position as the load is decreased or removed. With this construction, the metal cap is not held in the extended position after the load'is removed, as is the case where the coefficient of friction is such that the insulator head will not be lifted by the pressure exerted by the cap. In order to prevent a hard spot, this type of construction may be used in combination with resilient members having slots 17, as shown in my previous patent referred to above.

The invention may be applied in several different ways. The inner surfaces of the dielectric can be provided with bearing faces similar to the outside or the compensating bearing s faces may be placed against the metal forming the cap with cement adjacent to the porcelain or dielectric. It is generally much more diiiicult, however, to place the compensating bearings on the inner surface of a piece than on the outer surface. The compensating means may be spaced from either the bearing surface of the metal or the dielectric and can simply be placed in the cement joint.

Fig. 2 shows one form in which a compensator is placed in the cement joint. The balls or rollers '71 are enclosed in a sheet metal envelope '72 having curved walls such that relative movement of the parts in the direction of the load will tend to spread the joint. When the load is applied, there will be a tendency for the opposite sides of the envelope to roll or move relative to each other and to the members 71. t is, of course, essential that the size of the corrugations in the sheath be limited so that a rolling action will result and not a locking action. As the sheath 72 moves with respect to the rollers or balls '71, the two sides of the envelope will be spread apart, thereby compensating for any distortion. A compensating pocket or bearing of this kind may be placed vertically in a joint or at an angle and it may be composed of one or more parts, if desired. The roller members may be made of a coil spring, as shown at 73 in Fig. 4:, or may be of oval section, as shown at 74 in Fig. 3. It is evident that a pocket of this kind will act to restore the displaced parts when the load is relieved and pressure exerted by the cap. The members 72, 73 and 74 may be close together or separated. Where the parts are made of noncorrosive materials, the compensating pockets or joints may be placed in the cement; the latter providing for any unevenness in the metal or dielectric parts. Projections, as shown at 75, may be provided to hold the envelope in place in the cement. A compensating joint of this kind may be applied between insulating shells or members in pin type and bus insulators, or between the metal parts. While it is possible that the rolling bearing members may bear directly upon the cement or main metal surfaces, any

material movement extending over a long period of time when the rollers bear directly on the cement is likely to cause the cement to be pulveriaed and destroy the joint.

If the envelopes, which furnish the bearing and permit easy assembly, are not used, the space between the connected parts and the rolling members is usually filled with paraffin or wax. This forms a matrix so that the cement surface has the proper contour. This construction is shown in Fig. 5, as applied to the pin. The rolling members 76 are shown in the form of a small spiral tube, the space inside the tube and between the turns being filled with wax or paraffin '77 which forms a matrix for forming the cement 65. After the hardening of the cement, the wax may have little or no function and may be melted out if desired.

,I claim:

1. An insulator comprising a plurality of parts connected together by cement, roller bearings interposed in said cement, and a guard for excluding said cement from said roller bearings.

2. An insulator comprising a plurality of parts, roller bearings interposed between said parts, and a sheet metal envelope enclosing said roller bearings.

3. An insulator comprising a dielectric memher having a conical bearing surface, antifriction roller bearing means arranged to bear on said surface and having the axis of rotation thereof disposed circumferentially of said bearing surface, a fitting for said dielectric member, cement for securing said fitting to said dielectric member, and a guard member engaging said anti-friction rollers and excluding the cement therefrom.

4. An insulator comprising cooperating parts, one of said parts having an inclined bearing surface, cement for securing said parts together, roller bearing members engaging said bearing surface, and a guard engaging the sides of said roller bearing members opposite said bearing surface and excluding cement from said bearing.

5. An insulator comprising nested parts having wedging bearing surfaces for transmitting the force of the load on said insulator from one of said parts to the other, said parts being relatively movable in the direction of their axis to maintain bearing relation between said wedging surfaces notwithstanding differential radial expansion or contraction of said parts, and a roller bearing interposed between said surfaces and having its axis of rotation extending in a plane transverse to the axis of said parts and having clearance for rolling movement on said surfaces when said parts are relatively displaced in the direction of their axis.

6. An insulator comprising a dielectric member and a metal member, said members having cooperating wedging bearing surfaces for transmitting the load from one of said members to the other, and roller bearing means interposed between said surfaces, said members and roller bearing means having clearance to permit members to move relative to each other on said roller bearing means to compensate for distortion of said members.

'7. An insulator comprising a metal and a dielectric member, one of said members having a wedging bearing surface, cement for connecting said members and for forming a bearing surface cooperating with said wedging bearing surface, roller bearing means interposed between said cement and said wedging bearing surface, and means disposed adjacent said roller bearing means to provide a matrix to form a bearing surface on said cement to cooperate with said roller bearing means and said wedging bearing surface.

8. An insulator comprising a pair of connected members having cooperating wedging bearing surfaces for transmitting the load from one of said members to the other, one of said members being of fragile dielectric material and plurality of resilient rollers disposed side by side and interposed between said wedging bearing surfaces to distribute the lead over said surfaces and to facilitate movement of said surfaces relative to each other to enable said wedging surfaces to compensate for relative distortion of said members.

9. An insulator comprising a dielectric member having a recess therein, a pin disposed in said recess, said pin having a conical bearing surface, cement disposed in said recess surrounding said pin and providing a bearing surface for cooperation with the bearing surface of said pin, said pin and dielectric member being relatively movable in the direction of the axis of said pin to enable said bearing surfaces to compensate for relative distortion of said pin and dielectric member, and roller bearing means surrounding said conical bearing surface and interposed between the bear surfaces of said pin and said cement to facilitate relative movement of said bearing surfaces when said pin and dielectric member movc relative to each other in the direction of their axis, said roller bearing means being rotatable about an axis extending circumferentially of said insulator.

10. An insulator comprising a dielectric member having a recess therein, a pin disposed in said recess, said pin having a conical bearing surface, cement disposed in said recess about said bearing surface, and a plurality of helical spring rollers disposed about said pin and interposed between said cement and said conical bearing surface and having their axes disposed circumferentially of said bearing surface.

11. An insulator comprising a dielectric member. metal fitting secured to said dielectric member, a metal stress distributor interposed between said dielectric member and metal fitting for transmitting force between said member and fitting, said stress distributor and fitting having cooperating wedging bearing surfaces, and a roller interposed between said surfaces and having rolling contact with said surfaces.

12. An insulator comprising a dielectric member, a metal fitting secured to said dielectric member, a metal stress distributor interposed between said dielectric member and metal fitting for transmitting force between said member and tting, said stress distributor and fitting having cooperating wedging bearing surfaces, and a resilient roller interposed between said surfaces and having rolling contact with said surfaces.

13. An insulator comprising a dielectric men a metal fitting for said member, a metal stress distributor interposed between said dielectric member and fitting and fixed to said dielectric member, said stress distributor and fitting having cooperating conical bearing faces for transmitting the load on said insulator, and

roller bearing interposed circumferentially betwe said bearing surfaces and having clearance for movement along said surfaces transverse to the a :is of said roller bearing, said roller being pcnsible and contractible longitudinally of its axis to facilitate rolling thereof when said su faces move relative to each other.

14. An insulator pin adapted to be secured in a recess in dielectric member, said pin having a plurality of wedging bearing surfaces distributed over a zone extending longitudinally of said pin, a radially yieldable thimble surrounding a portion of said pin and having bearing surfaces opposing the wedging bearing surfaces on said pin, and rollers interposed between the opposed bearing surfaces. on said pin and having their axes of rotation disposed circuinferentially of said pin and thimble and having clearance to permit rolling movement of said rollers on said surfaces when said pin. and thiinble are moved relative to each other in the direction of their axis.

15. An insulator pin having a plurality of wedgbearing surfaces distributed over a Zone extending longitudinally of said pin, a thimble surrounding said zone and bein adapted to be secured in a recess in a dielectric member, said thimble being radially yieldable and having wedging bearing surfaces opposed to the wedging bearing surfaces on said pin. and yielding rollers interposed between the bearing surfaces on said pin and thimble and having their axes of rotation disposed circumfercntially of said pin and having clearance to permit rolling movement thereof on said surfaces.

16. A metal fitting for an insulator having a plurality of wedging bearing surfaces distributed over a zone extending in the direction of the axis of said fitting, a thi .ble coaxial in aid fitting and having wedging bearing faces opposed to the bearing surfaces on said fitting, said thimble being adapted to have the surface thereof cpposite said fitting secured to a dielectric member, and yielding rollers interposed between the bearing surfaces on said fitting and thimble and having the axes of rotation thereof disposed circumferentially of said fitting, said rollers having clearan e to permit rolling movement thereof on said bearing surfaces.

17. A fitting for insulator comprising rela tively movable parts having cooperating, overhanging wedging bearing surfaces for compensatfor relative distortion. of the parts, and resilient means acting on said bearing surfaces to restore the parts after relative movement thereof.

18. An insulator having conical. overhanging bearin surfaces disposed one within the other and drawn together by the load on the insulator, and a spring acting on said bearing surfaces and tending to move said surfaces relative to each other in a direction opposed to the direction of the movement produced by the load.

19. An insulator comprising connected parts having cooperating bearing surfaces and a rolling member interposed between said surfaces, said rolling member bein variable in length to compensate for variations in said surfaces transverse to the direction of the relative movement of said surfaces.

20. An insulator comprising conical members disposed one within the other and having cooperating bearing surfaces, and roller bearing members interposed between said surfaces and having their axes of rotation extending circumferentially of said surfaces, said bearing members being axially extensible to conform to portions of said conical bearing surfaces having different diameters.

21. An insulator comprising conical members disposed one within the other and having operating bearing surfaces, and roller bearing members having their axes extending circumferentially about the inner one of said members, said bearing members comprising helical springs disposed side by side.

22. An insulator comprising conical members disposed one within the other and movable relative to each other in the direction of their common axes, and a roller bearing member interposed between the conical surfaces of said members, said bearing member extending circumferentially of said surfaces and having a flexible axis and being longitudinally extensible.

23. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating conoidal bearing surfaces for transmitting the load and for compensating for distortion of said parts and roller bearing means interposed between said surfaces, said roller bearing means having the axis of rotation thereof extending circumferentially of said conoidal surfaces and having travelling rolling contact with the conoidial surface of each of said parts.

24. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating nested conoidial bearing surfaces for transmitting the load on said insulator and for compensating for distortion of said parts, and roller bearing means interposed between said surfaces and having the axis of rotation thereof extending circumferentially of said surfaces and having travelling rolling contact with the bearing surfaces of each of said parts, said bearing means being extensible in the direction of the axis thereof to compensate for differences in the circumference of said surface at different points thereon.

25. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating nested conoidial bearing surfaces for transmitting the load on said insulator and for compensating for distortion of said parts, and roller bearing means interposed between said surfaces and having the axis of rotation thereof extending circumferentially of said surfaces, said axis being capable of flexing to permit rotation of said bearing means while in contact with said surfaces, said roller bearing means having travelling rolling contact with the bearing surfaces of each of said parts.

26. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating nested conoidal bearing surfaces for transmitting the load on said insulator and for compensating for distortion of said parts, and roller bearing means interposed between said surfaces and having the axis of rotation thereof extending circumferentially of said surfaces, said axis being capable of flexing to permit rotation of said bearing means while in contact with said surfaces and being longitudinally extensible and contractible to compensate for variations in the circumference of said surfaces at different points thereon, said roller bearing means having travelling rolling contact with the bearing surfaces of each of said parts.

27. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating nested conoidal bearing surfaces for transmitting the load and for compensating for distortion of said parts, and hollow flexible spring roller bearing means interposed between said surfaces and having travelling rolling contact with the bearing surfaces of each of said parts, said roller bearing means being rotatable about an axis extending circumferentially of said insulator.

28. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating nested conoidal bearing surfaces for transmitting the load and for compensating for distortion 01. said parts, and helical spring roller bearing means interposed between said surfaces and extending circumferentially thereof and having travelling rolling contact with the bearing surfaces of each of said parts.

29. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating wedging bearing surfaces for transmitting the load and for compensating for distortion of said parts, and roller bearing members interposed between said surfaces, said roller bearing members having travelling rolling contact with the bearing surface of each of said parts.

30. An insulator comprising a plurality of parts, one of which is a dielectric member, said parts having cooperating tapered bearing surfaces for transmitting the load from one part to the other, roller bearings interposed between said parts, a guard member for said roller bearings and cement interposed between said guard member and one of said parts and separated from said roller bearings by said guard member, said roller bearings having travelling rolling contact with said guard member.

31. An insulator comprising a plurality of parts having cooperating bearing surfaces, roller bearings interposed between said bearing surfaces, an envelope of sheet material enclosing said roller bearings, and cement for securing said envelope and enclosed roller bearings in place between said bearing surfaces.

32. An insulator comprising a plurality of parts, roller bearing means interposed between said parts and having the axis of rotation thereof disposed circumferentially of said parts, said parts having undulated bearing surfaces engaging said roller bearings and having clearance adjacent said bearings to permit the bearings to roll on said surfaces whereby said parts are separated by relative movement of said surfaces on said roller bearings.

ARTHUR O. AUSTIN.

Patent No. L94,265.

Mareh 12, 1935.

*ihe printed speeification 0 the vs: Page 3. seeoad eeiumn, eeagenmtieg; and that the said Letters an E I line 65, claim 17, for "eeexp Feminishould be reed with this eea'reee the reward of the ease ie the Famit igeed and sealed this 9 in e g; er;

Aeiing ilemmissinner e? Patents.

- Patent No. L94,265. Marsh 12, 1935.

ARTHUR 0. AUSTIN.

it is hereby certified that error apgears in the printed specification oi the ebeve numbered patent requiring eorrectien as ieilows: Page 3. seeozld column,

line 65, claim 37, for "CGBEEEQEISQF" reed cemgensating; and that the said Letters Patent siiouid be read with this eerreetien therein tiiat the same may conform to the reeerd of the ease in the Patent @ttiee.

Signed and sealed this'9tii day ei Agril, A. D. 1935.

Leslie Frazer (Seat) Acting (lemmissinner of Patents. 

